Which London Underground line is the busiest?

This is the Overground and very much not the Tube, but it's pretty busy, so go figure. Image: Matt Buck

All London commuters are perpetually convinced that their commute – theirs, not yours – is the most hellish, the most jam-packed, the most arduous and hard-going.

But not all commutes are born equal. Some lines are hotter than others, some lines have older trains than others, and some lines are busier than others.

So what is the truth? Which route is the busiest?

Part of the problem is that we don’t have all the data – the beautiful, cold, hard data – we need to make this calculation properly, because TfL doesn’t divulge everything. So though you can publicly access a very nerdy document called the London Underground Performance Data Almanac, which is published every year with juicy stats about ‘lost customer hours’ and ‘number of engineering runs’ and suchlike, the data on passenger journeys is rather lacking.

The document will tell you that there were 1,377,850,000 journeys made on the London Underground network in 2016-17; but it won’t break down that data for you by individual line. Which is rather annoying.

It wasn’t always this way, though.

You can still find archived copies of this document from previous years, in which these figures are given. The last set of figures we have are from 2011112, and show a total of 1,170,512,000 journeys across the London Underground network, broken down into individual lines.

This will tell you which line was the busiest in overall terms – how many journeys were taken on it – which runs as follows, from busiest to least-used.

1. Central, 260.9m

2. Northern, 252.3m

3. Jubilee, 213.6m

4. Piccadilly, 210.2m

5. District, 208.3m

6. Victoria, 200.0m

7. Circle and Hammersmith & City lines, 114.6m

8. Bakerloo, 111.1m

9. Metropolitan, 66.8m

10. Waterloo & City, 15.9m

But this raises all sorts of questions.

The Central Line, looking not that busy. Image: Twyman1998.

One, of course, is why the Circle and Hammersmith & City lines have been lumped together, when they perform reasonably different functions and spend a lot of time apart (despite clinging to each other at times).

The other of which is why do 111,136,000 people enjoy inflicting pain on themselves so much that they would willingly use the Bakerloo line.

(Am I joking? Am I not? Who knows.)

On a more serious note, this way of looking at things is obviously flawed. The Waterloo & City lines, with its two stations and 1.5 miles of track, cannot sensibly be considered in the same terms as the Metropolitan line, with its 34 stations and 41.4 miles of track.

The Metropolitan Line, speeding along. Image: Matt Buck

We must think again.

The logical thing to do at this point is to take the total number of passenger journeys per year, and divide it by the number of miles of track there are. Then, you can tell – in a roundabout way – how many people there are per mile of track. Thus, you work out how busy the line is.

Working through this system obviously reveals starkly different results. Here we go:

1. Victoria, 15.1m per mile

2. Waterloo & City, 10.6m per mile

3. Jubilee, 9.5m per mile

4. Bakerloo, 7.7m per mile

5. Northern, 7.0m per mile

6. Central, 5.7m per mile

7. District, 5.2m per mile

8. Piccadilly, 4.7m per mile

9. Circle and Hammermith & City, 4.7m per mile

10. Metropolitan, 1.6m per mile

So there, apparently, you have it. The Victoria is the busiest, the diddly little Waterloo & City is next, and the dribbly Metropolitan (read: Rural) Line might as well be empty.

The Victoria Line at Brixton, looking not at all busy. Image: Oxfordian Kissuth.

Of course, the world has changed a lot since 2011. Heck, we didn’t even know about avocados in 2011, so who knows what the shape of the network is nowadays. Perhaps the Metropolitan has got even more empty, or the troupe of masochists on the Bakerloo has thinned out.

At a guess, I’d imagine that the parts of the network serving the eastern inner London boroughs – like the eastern chunk of the Central and District lines – may have become busier, but as we don’t have the facts, that’s nothing more than an idle guess.

It’s also slightly unclear as to how these figures are reached, as beyond station entries and exits, TfL doesn’t actually have that much info on which lines you take – at least, it didn’t until recently when it worked out how to track you if you used the Tube’s WiFi.

So in 2011, the tube didn’t know if you went from Baker Street to Mansion House via one change at Westminster, two changes at Moorgate and Bank/Monument, or some spurious combination of Euston Square, Charing Cross, and Embankment (weird, but why not?).

After a TfL pilot tracking depersonalised WiFi data, we may soon better understand not only which lines are the busiest, but which specific sections of track are the busiest: it may, for example, emerge that the Victoria line between Oxford Circus and Warren Street is the busiest part of the Tube.

For now, we don't know. As ever, in life, attempting to know anything only reveals how little you know about everything.

Cheerful, huh?

Enjoy your neighbours’ armpits all you Victorianas. 

Jack May is a regular contributor to CityMetric and tweets as @JackO_May.

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Here are the seven most extreme plants we’ve so far discovered

Artist's impression of Kepler-47. Image: NASA.

Scientists recently discovered the hottest planet ever found – with a surface temperature greater than some stars.

As the hunt for planets outside our own solar system continues, we have discovered many other worlds with extreme features. And the ongoing exploration of our own solar system has revealed some pretty weird contenders, too. Here are seven of the most extreme.

The hottest

How hot a planet gets depends primarily on how close it is to its host star – and on how hot that star burns. In our own solar system, Mercury is the closest planet to the sun at a mean distance of 57,910,000km. Temperatures on its dayside reach about 430°C, while the sun itself has a surface temperature of 5,500°C.

But stars more massive than the sun burn hotter. The star HD 195689 – also known as KELT-9 – is 2.5 times more massive than the sun and has a surface temperature of almost 10,000°C. Its planet, KELT-9b, is much closer to its host star than Mercury is to the sun.

Though we cannot measure the exact distance from afar, it circles its host star every 1.5 days (Mercury’s orbit takes 88 days). This results in a whopping 4300°C – which is hotter than many of the stars with a lower mass than our sun. The rocky planet Mercury would be a molten droplet of lava at this temperature. KELT-9b, however, is a Jupiter-type gas giant. It is shrivelling away as the molecules in its atmosphere are breaking down to their constituent atoms – and burning off.

The coldest

At a temperature of just 50 degrees above absolute zero – -223°C – OGLE-2005-BLG-390Lb snatches the title of the coldest planet. At about 5.5 times the Earth’s mass it is likely to be a rocky planet too. Though not too distant from its host star, at an orbit that would put it somewhere between Mars and Jupiter in our solar system, its host star is a low mass, cool star known as a red dwarf.

Freezing but Earth-like: ESO OGLE BLG Lb. Image: ESO/creative commons.

The planet is popularly referred to as Hoth in reference to an icy planet in the Star Wars franchise. Contrary to its fictional counterpart, however, it won’t be able to sustain much of an atmosphere (nor life, for that matter). This because most of its gases will be frozen solid – adding to the snow on the surface.

The biggest

If a planet can be as hot as a star, what then makes the difference between stars and planets? Stars are so much more massive than planets that they are ignited by fusion processes as a result of the huge gravitational forces in their cores. Common stars like our sun burn by fusing hydrogen into helium.

But there is a form of star called a brown dwarf, which are big enough to start some fusion processes but not large enough to sustain them. Planet DENIS-P J082303.1-491201 b with the equally unpronounceable alias 2MASS J08230313-4912012 b has 28.5 times the mass of Jupiter – making it the most massive planet listed in NASA’s exoplanet archive. It is so massive that it is debated whether it still is a planet (it would be a Jupiter-class gas giant) or whether it should actually be classified as a brown dwarf star. Ironically, its host star is a confirmed brown dwarf itself.

The smallest

Just slightly larger than our moon and smaller than Mercury, Kepler-37b is the smallest exoplanet yet discovered. A rocky world, it is closer to its host star than Mercury is to the sun. That means the planet is too hot to support liquid water and hence life on its surface.

The oldest

PSR B1620-26 b, at 12.7bn years, is the oldest known planet. A gas giant 2.5 times the mass of Jupiter it has been seemingly around forever. Our universe at 13.8bn years is only a billion years older.

Artist’s impression of the biggest planet known. Image: NASA and G. Bacon (STScI).

PSR B1620-26 b has two host stars rotating around each other – and it has outseen the lives of both. These are a neutron star and a white dwarf, which are what is left when a star has burned all its fuel and exploded in a supernova. However, as it formed so early in the universe’s history, it probably doesn’t have enough of the heavy elements such as carbon and oxygen (which formed later) needed for life to evolve.

The youngest

The planetary system V830 Tauri is only 2m years old. The host star has the same mass as our sun but twice the radius, which means it has not fully contracted into its final shape yet. The planet – a gas giant with three quarters the mass of Jupiter – is likewise probably still growing. That means it is acquiring more mass by frequently colliding with other planetary bodies like asteroids in its path – making it an unsafe place to be.

The worst weather

Because exoplanets are too far away for us to be able to observe any weather patterns we have to turn our eyes back to our solar system. If you have seen the giant swirling hurricanes photographed by the Juno spacecraft flying over Jupiter’s poles, the largest planet in our solar system is certainly a good contender.

However, the title goes to Venus. A planet the same size of Earth, it is shrouded in clouds of sulfuric acid.

The ConversationThe atmosphere moves around the planet much faster than the planet rotates, with winds reaching hurricane speeds of 360km/h. Double-eyed cyclones are sustained above each pole. Its atmosphere is almost 100 times denser than Earth’s and made up of over 95 per cent carbon dioxide.

The resulting greenhouse effect creates hellish temperatures of at least 462°C on the surface, which is actually hotter than Mercury. Though bone-dry and hostile to life, the heat may explain why Venus has fewer volcanoes than Earth.

Christian Schroeder is a lecturer in environmental science and planetary exploration at the University of Stirling.

This article was originally published on The Conversation. Read the original article.